Chad Orzel - A Brief History of Timekeeping: The Science of Marking Time, from Stonehenge to Atomic Clocks

Contents

PRAISE FOR A BRIEF HISTORY OF TIMEKEEPING

As Chad Orzel shows in his informative new book, while the pace of modern life seems to march briskly in step with the rhythms of various clocks, keeping accurate time has been a mainstay of historya driving force for astronomical measurements, and eventually classical and relativistic physics. A Brief History of Timekeeping offers the quintessential account of all the factors that make up ways we record timefrom the relatively slow progression of daily and lunar cycles to the near-instantaneous speed of atomic transitions. Orzels fascinating chronicle of how we measure the seconds, days, and years that set the stride of our lifes journey is well worth making the time to readand that literary adventure will fly by, no doubt.

Paul Halpern, author of Flashes of Creation: George Gamow, Fred Hoyle and the Great Big Bang Debate

Orzel gives us the grand tour of something we all take for granted. Its about time.

Chris Ferrie, coauthor of Where Did the Universe Come From? And Other Cosmic Questions and author of Quantum Physics for Babies

Each day in 2019, Chad Orzel informs us, is nearly two milliseconds longer than days were in 1870. And they feel even longer. This entertaining and engrossing book takes us through our long struggle to measure time with precision. Filled with amazing devices, its ultimately a story of the triumph of human ingenuity.

Sean Carroll, author of Something Deeply Hidden: Quantum Worlds and the Emergence of Spacetime

A deliciously detailed journey through the astonishing ticks and tocks of timekeeping, from neolithic henges and Mayan number systems to cinnamon-filled sandglasses, tuning fork wristwatches, and even the northern lights. Equal parts mesmerizing and fascinating, Orzels beautifully clear explanations of physics illuminate subjects from planets to quantum engineering. By the end it is clear that time may never be on our side, but keeping track of it has opened up the universe for us.

Caleb Scharf, author of The Ascent of Information: Books, Bits, Genes, Machines, and Lifes Unending Algorithm

If theres one feat our species has truly mastered, its slicing and dicing time into ever-shorter intervals, and keeping track of those ticks and tocks with mind-boggling precision. Todays best atomic clocks can track time with a precision of one part in a billionbut getting to this point, as Chad Orzels entertaining new book shows, has been an incredible adventure. Its a history of technology, of course, but we also learn about the underlying science, from the ancient astronomers who first made sense of the motions of the sun, moon, and stars to those who unveiled relativity and quantum mechanics in the last century. If you like science, history, and fun in equal measure, A Brief History of Timekeeping is for you.

Dan Falk, science journalist, author, and broadcaster

A fascinating intersection of science, history, and theology. I never expected to lose track of time reading a book about time.

James Breakwell, comedy writer, creator of @XplodingUnicorn on Twitter, and author of How to Be a Man (Whatever That Means)

A BRIEF HISTORY OF TIMEKEEPING

ALSO BY CHAD ORZEL

Breakfast with Einstein: The Exotic Physics of Everyday Objects
Eureka: Discovering Your Inner Scientist

How to Teach Relativity to Your Dog

How to Teach Quantum Physics to Your Dog

A Brief History of Timekeeping copyright 2022 by Chad Orzel

All rights reserved. No part of this book may be used or reproduced in any manner whatsoever without written permission of the publisher, except in the case of brief quotations embodied in critical articles or reviews.

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First E-Book Edition: January 2022

Library of Congress Control Number: 2021040500

ISBN 9781953295606 (trade paper)

ISBN 9781953295941 (electronic)

Editing by Laurel Leigh and Alexa Stevenson

Copyediting by Scott Calamar

Proofreading by Denise Pangia and Cape Cod Compositors, Inc.

Indexing by WordCo Indexing Services, Inc.

Text design and composition by Aaron Edmiston

Cover design by Pete Garceau

Cover image iStock / mladn61, robas, Wylius, and Nastco

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For my grandmother, Ann Ryan,
who is such a pivotal part of our family history.

Contents

T he picturesque campus of Union College in Schenectady, New York, where I teach, features lush, green quads surrounded by columned buildings full of classrooms, labs, and offices. Like most college campuses, its also full of clocks. Theres the tower clock in Memorial Chapel, whose chimes regularly ring out to mark the hours (and showcase the talents of the student musicians who occasionally take over to play tunes on the chimes). A large decorative clock, a gift of the class of 1997, stands in front of the Reamer Campus Center, where it serves as a landmark for meeting people. Almost every classroom sports an analog clock on the wall, for students and faculty to track the progress of class hours (too fast for the faculty, too slow for the students). And, of course, there are innumerable unseen clocks: embedded in every computer, worn as wristwatches, carried in smartphones.

Even beyond the physical presence of clocks, the tracking of time is ubiquitous on campus. Classes are scheduled down to the minutestart at 9:15 AM , end at 10:20 AM , start again at 10:30 AM in a different roomand meetings and appointments fill the day. Student work is often timed10 minutes allotted for an in-class presentation, an hour to complete an examand athletic feats are recorded down to fractions of a second. On a slower scale, the academic year progresses through a stately cycle of marked dates: the opening convocation, the start and end of the academic term, the annual Steinmetz Symposium celebrating student research. Every day brings students and faculty closer to the commencement ceremony that ends the year and sends a new class of graduates off into the world.

All of this tracking and measuring of time is generally regarded as too routine to be commented upon. Whats too often overlooked in the process of keeping on schedule (and fretting about being overscheduled) is the depth of history and rich variety of science underlying all this activity. We tend to think of our preoccupation with time as a modern phenomenon, but in fact the tracking of time has been a major concern in essentially every era and location that we find evidence of human activity. Every historical society we know of had its own ways of tracking the passage of time, some of them dizzyingly complicated. Some of the most ancient architectural monuments we know of are calendar markers.

A Brief History of Timekeeping is a virtual journey through the science that grew up alongside centuries of human efforts to measure the passage of time. Starting with the oldest known solstice-marking monuments, we will explore the astronomy of the solar system and the features that determine the suns path across the sky. Efforts to better understand the motion of the sun and planets led to the development of Newtonian physics, and well see how this enables the technology to build mechanical clocks. And well discuss revolutionary developments in the physics of electromagnetism and quantum mechanics that eventually led to the replacement of standards of timekeeping based on the motion of physical objects (like the pendulum of a mechanical clock) by modern atomic clocks that count the oscillations of light.